1. Field of the Invention
The present invention relates generally to surgical implements for griping tissue, and more particularly to forceps used to grasp the vagus nerve while conducting surgical interventions in the lower esophagus or stomach.
2. Description of Related Art
A commonly used instrument in performing surgical interventions is a standard forceps, such as Allis forceps. The standard forceps comprises a scissor-like construction that includes a locking mechanism for the two arms at the handle end. The grasping tips, at the ends of the arms opposite the handles, have mating sawtooth extensions, which meet in a line perpendicular to the lengthwise extension of the instrument and are used to clamp onto tissue.
Because of the large, flattened area defined by the tips of standard forceps, additional tissue is often grasped during a surgical operation and elevated along with the target tissue to be grasped. For example, the vagus nerve, like many other nerves, lies in close proximity to vascular tissue such as veins and arteries, and is, along with such other tissues, cloaked in mesenteric tissue. Moreover, a nerve, although having moderate resilience to stretching thereby allowing an instrument to be placed loosely beneath the nerve to retract it from a surgical site, is particularly vulnerable to crushing, the consequence of which may include faulty neurological transmission due to an interruption of electrical conduction caused by irreparably crushing of cells. Because the vagus nerve has a large diameter, exceeding 4 mm in places, to pull it up and out of an incision area with the larger, flattened areas of the tips of the closed jaws of the a standard forceps would likely cause crushing, and at best pinching as a result of the nerve bending over the edged surfaces of the jaws. Thus, the large ends and clamping structure defined by the standard forceps is particularly unsuited for use to grasp and retract the vagus nerve. Moreover, due to the open ends of the grasping tips, tissue often slips out of the grasp of the instrument when the nerve is lifted clear. In each case, the surgeon is required to recapture the tissue, and recommence this part of the procedure. Such imprecision and slippage renders the procedure longer, and more difficult to conduct than if a forceps with a design more specific to the procedure were used.
Another common instrument is the rod clamp used with a threaded rod in orthopedic surgery. The clamp has a blunt, widened tip, defining an aperture for passage and clamping of the rod. Whereas the aperture may allow passage of any tubular item, the blunt, wide tip and short jaws prevent the rod clamp from use for fine manipulations in a wound site, such as finding a nerve in an already occluded area. The short, wide, blunt jaws would act to block the view of the wound site. Moreover, because the end of the jaws are very near the pivot stud joining the two arms of the clamp to allow a scissoring action of the clamp, the arms must be widely spread apart for open the jaws to open sufficiently at the opposite end to accept the vagus nerve. This would require a surgeon to have a very large hand span in order to operate with difficulty at best.
Several attempts have been made to overcome the problems associated with the use of standard forceps in procedures requiring manipulation of stranded or tubular tissues. U.S. Pat. No. 2,397,823, issued to Carl W. Walter, on Apr. 2, 1946, discloses a forceps intended to be capable of grasping a wide variety of objects. This forceps has a elongated "pistol-grip" handle. It is oriented at an angle of at least 45 degrees relative to a gripping portion of the device. The forceps of Manual V. Santos shown in U.S. Pat. No. 3,828,791 issued Aug. 13, 1974 utilizes a similar functional design. Consequently, minute manipulations of tissue during a surgical procedure would be cumbersome at best, and dangerous at worst.
Moreover, the Walter forceps is shown to have serrations on the very tip. Such serrations, while providing additional gripping friction, would necessarily cause destruction of surrounding tissue. Also, the presence of these serrations clearly indicate that this forceps has a clamping hole substantially recessed from the end of the device, in stark contrast with applicant's own invention. Use of such a device in a retraction of the vagus nerve would require a larger incision than necessary to pass the device into the wound site sufficiently far for the clamping hole to engage the vagus nerve; moreover, it would cause tissue damage when the device is closed and clamped around the nerve. It would also make the lifting of the vagus nerve impossible without substantial destruction of surrounding, additional tissue caught in the large extension of the forceps' tips beyond the clamping hole, in turn resulting in additional, unwarranted procedure length, trauma, and danger.
Both the Santos and Walters devices fail to have a beveled rim around the edge of the hole nearer its grasping end to provide effective gripping for lifting stranded tissue such as the vagus nerve. Instead, the Walters device has "arcs of different curvature" disposed around the rims of recesses in the jaws, which are described as including an "almost blade-like inner edge." Such bladed arcs would tend to cut tissue held, making holding of tissue impractical and dangerous. In fact, the forceps is intended for use with objects other than tissue, such as needles and swabs. Importantly, the literature describing the use of this device does not even mention its use for vagus retraction and lifting.
U.S. Pat. No. 2,642,871, issued to Joseph Theurig, on Jun. 23, 1953, discloses a forceps suitable for grasping tubular objects, such as syringes. The forceps has a clamping aperture described and depicted as comprising "transverse inverted obtuse angular meeting faces." The difficulty concomitant of using such a device in lifting the vagus nerve is substantial. Because the aperture is not curved to the shape of a tubular strand such as the vagus nerve, the vagus nerve would tend to both slide laterally and rotate within the aperture, if not be pinched during full closure with the tips contacting one another. Making the device smaller, so that the device would immovably hold the vagus, would result in failure of the device to close completely, as shown in FIG. 4 of the Theurig patent. Without complete closure, the device would tend to allow undesired release of the vas deferens during required lifting. The Theurig forceps also lacks a beveled rim around the edge of the hole nearer its grasping end to provide effective gripping of tubular tissue. Notably, the literature referring to the use of this device does not even mention use for retracting the vagus nerve.
U.S. Pat. No. 5,067,958, issued to Jeffrey J. Sandhaus, on Nov. 26, 1991, demonstrates a complicated apparatus intended to be used in procedures for implanting locking clips for clamping and occluding tubular vessels, such as the vas deferens during a vasectomy. Whereas the device includes a curved clamping hole appropriate for immovably holding a tublar vessel with the tips contacting one another, the clamping hole is relatively far removed (in comparison with applicant's own invention) from the end of the apparatus, as shown in FIG. 45 of the Sandhaus patent. Use of such a device in a vagus lifting procedure would cause tissue damage while the device is passed sufficiently far into the wound site for the clamping hole to engage the vagus; cause tissue damage when the device is closed and clamped around the vagus nerve; and, make the procedure's lifting of the vagus impossible without substantial destruction of surrounding tissue, because of additional tissue caught in the large extension of the forceps' tips beyond the clamping hole. The Sandaus forceps also fails to provide a beveled rim around the edge of the hole nearer its grasping end to provide effective grasping during lifting of a tubular tissue to prevent lateral slippage of the instrument along the tubular tissue.
British Patent No. 2,227,200, issued to Malcolm Charles Holbrook, on Jul. 25, 1990, discloses a forceps used for holding a catheter or organ duct during the course of a surgical procedure. This forceps has a three-millimeter clamping hole centered five millimeters from the end of the forceps, a relatively large distance (many times as large as the applicant's own invention) that makes the device unusable for the vagus retracting procedure. This forceps was designed for its invisibility to X-rays used during a surgical procedure, and not for use in vagus retractions. The Holbrook forceps also lacks a beveled rim around the edge of the hole nearer its grasping end to provide effective gripping a vagus nerve. The large end design of the Holbrook patent has a clasping, rather than grasping function, and is unsuitable for use with nerve tissue due to the risk of crushing.
Other inventions have similar disadvantages. UK Patent Application No. 2 210 574 to James Richard Smith describes a forceps with triangular head, including a bridge defining an aperture for gripping a suture needle. None of the devices shown therein can grasp a vagus nerve without clamping down upon it, causing crushing. This disadvantage is likewise true of the surgical forces with notches for accommodating suture needles as shown in U.S. Pat. No. 4,26,241 issued Oct. 7, 1980 to William E. Walker, Jr. USSR Patent No. 145,976 shows a pair of forceps, having serated teeth provided along a substantial portion of the tip before an aperture is provided. Like the previously mentioned devices, the serated tip increases the risk of crushing and increased trauma due to insertion of the tip into surrounding tissue. USSR Patent No. 1321409 shows a pair of forceps, having semi-circular jaws with intermittant sets of serated teeth. USSR Patent No. 219095 shows a pair of forceps, having open-ended tipped jaws moulded to the same shape as a prosthesis for the long branch of the anvil in the ear; the open-ended tips are unsuitable for retracting a tubular tissue, allowing it to slip from the open-ends.
Finally, European Patent Application by applicant Fritz Lolagne published Jan. 25, 1995, contemplates forceps generally sized to closely conform to the cross-sectional shape of the vas deferens and vagus nerve, providing preferred diameters of the enclosing aperture at the tip of the forceps to be 0.40 centimeters in length and 0.30 centimeters in width. The application fails to disclose the crested ridge or the hourglass profile of the present invention.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, a forceps solving the aforementioned problems is desired.